1. Field of the Invention
The present disclosure relates to electric motors. The present disclosure relates in particular to armatures for electric motors and to the arrangement of switching wires and of coil wires on the armature.
2. Brief Description of the Related Art
Armatures of brushed electric motors comprise coils wound around the teeth of the armature for providing the required magnetization of the teeth of the armature. Magnetisation of the teeth is done by applying an electric current through the coil. The coils are electrically contacted via brushes and a commutator in a general known manner. While an electric motor has at least two coils and two teeth, modern electric motors have a plurality of teeth such as for example four or more teeth. A coil is wound around each tooth or a plurality of teeth and individually addressed via the commutator.
While the armature may be seen as having a plurality of teeth arranged around the shaft, the armature can also be considered as having a plurality of cavities arranged between the teeth of the armature. Besides the coil wires, so called switching wires are arranged in the cavities between the teeth. The switching wires are used to connect the coils with the commutator and to electrically equalize single bars of the commutator. The arrangement of the coil wires and the switching wires with respect to each other depends on the manufacturing method or sequence. The arrangement of the switching wire and the coil is different depending on whether the switching wire is placed prior to or after the arrangement of the coil. This has the disadvantage that the position of the coil wires and the coil cannot be determined precisely and manufacturing sequence has to be considered. If the manufacturing sequence was not considered, in some cavities the switching wires will be arranged at the positions where coils are supposed to be arranged, so it is difficult to wind coils on teeth orderly, which will have several negative effects like uncontrolled wire crossings, increased end turn height, unbalance and efficiency degradation of motor.
It is an object of the present invention to overcome the disadvantages of prior art.